Electrophoretic isolation of saponin fractions from Saponinum album and their evaluation in synergistically enhancing the receptor-specific cytotoxicity of targeted toxins

Saponinum album (SA) is a commercial mixture of saponins isolated from Gypsophila species. In the previously published work, we reported that SA dramatically improves the inhibition of tumor growth by targeted toxins in mice in a synergistic way. Here we report a simplified electrophoretic method for the isolation of a highly effective fraction of SA with a relative electrophoretic mobility to the dye front (R(f) ) of 0.63 from the mixture. In total, four different fractions were separated at a preparative scale, and evaluated by ESI-MS, HPLC and TLC analysis. Electrophoretic mobility and electrochemical properties of the different fractions of saponins from SA were set into relation to their ability to enhance the cytotoxicity of epidermal growth factor (EGF)-based targeted toxins. We here treated HER-14 cells, which are NIH-3T3 Swiss mouse embryo cells transfected with the human EGF receptor. Untransfected NIH-3T3 cells served as control. The major bulk of SA (72.3%) (R(f) =0.78) migrated the farthest and was found to be significantly ineffective (p<0.05) in enhancing the cytotoxicity of the targeted toxin, while the second fraction (R(f) =0.63) showed an enhancement of 9800-fold. The third (R(f) =0.56) had an enhancement factor of 3200, the fourth (R(f) =0.08) was again significantly ineffective (p<0.05) in exhibiting any enhancement of cytotoxicity.     

Correlative microscopy: a powerful tool for exploring neurological cells and tissues

Imaging tools for exploring the neurological samples have seen a rapid transformation over the last decade. Approaches that allow clear and specific delineation of targeted tissues, individual neurons, and their cell–cell connections as well as subcellular constituents have been especially valuable. Considering the significant complexity and extent to which the nervous system interacts with every organ system in the body, one non-trivial challenge has been how to identify and target specific structures and pathologies by microscopy. To this end, correlative methods enable one to view the same exact structure of interest utilizing the capabilities of typically separate, but powerful, microscopy platforms. As such, correlative microscopy is well-positioned to address the three critical problems of identification, scale, and resolution inherent to neurological systems. Furthermore, the application of multiple imaging platforms to the study of singular biological events enables more detailed investigations of structure–function relationships to be conducted, greatly facilitating our understanding of relevant phenomenon. This comprehensive review provides an overview of methods for correlative microscopy, including histochemistry, transgenic markers, immunocytochemistry, photo-oxidation as well as various probes and tracers. An emphasis is placed on correlative light and electron microscopic strategies used to facilitate relocation of neurological structures. Correlative microscopy is an invaluable tool for neurological research, and we fully anticipate developments in automation of the process, and the increasing availability of genomic and transgenic tools will facilitate the adoption of correlative microscopy as the method of choice for many imaging experiments.     

The effects of a single stage-structured population model with impulsive toxin input and time delays in a polluted environment

Uncontrolled contribution of pollutant to the environment has led many species to extinction and several others are at the verge of extinction. This article deals with the dynamics of a single stage-structured population model with impulsive toxin input and time delays (including constant individual maturation time delay and pollution time delay) in a polluted environment, in which we assume that only the mature individuals are affected by pollutants. We obtain conditions for the global attractivity of the population-extinction periodic solution and the permanence of the population. We show that maturation time delay and impulsive toxin input can bring great effects on the dynamics of the system, and pollution time delay is harmless. Numerical simulations confirm our theoretical results.     

Bilateral vocal fold paralysis: an unsual treatment with botulinum toxin

We presented a patient with bilateral vocal fold paralysis treated with intralaryngeal Botox injection to improve the glottal airway. The use of Botox in this manner has not been previously reported and highlights the value and role of intralaryngeal Botox in changing the configuration of the glottis. The concept and various approaches for using Botox to alter pathologic vocal fold position is reviewed and discussed.     

Unilateral Versus Bilateral Injections of Botulinum Toxin in Patients with Adductor Spasmodic Dysphonia

Both unilateral and bilateral thyroarytenoid muscle injections of Botox provide effective management of voice symptoms in patients with adductor spasmodic dysphonia; however, the preferred injection technique has not been established. In this study, 16 patients were treated with unilateral injections (72 injections total) and 33 patients were managed with bilateral injections (133 injections total). Individual assignments to injection type were based on treatment previously received and dose was adjusted according to the patient's previous treatment response. An optimal treatment included a benefit lasting 3 months or more with side effects lasting 2 weeks or less. Compared to patients receiving bilateral injections, those receiving unilateral injections more frequently noted a benefit of 3 months or more (p = 0.03), side effects of 2 weeks or less duration (p = 0.03), as well as both a 3-month benefit and a 2-week or less side effect (p = 0.0004). Injection type had no effect on optimal Botox dosing with repeat injections. Successive unilateral injections at the same dose were more likely (p = 0.012) than successive bilateral injections to produce the same or longer duration of benefit. We conclude that a unilateral injection routine has a more optimal and consistent treatment effect/side effect profile.     

蝎毒素LmKTT-1a 与胰蛋白酶相互作用研究

LmKTT-1a 是最近发现的一个蝎毒素，该多肽分子不仅具有钾离子通道调节剂的功能，还具有胰蛋白酶（Trypsin）抑制剂的活性，是第一个被发现的双功能蝎毒素．虽然前期工作已对LmKTT-1a 的溶液结构和钾离子通道调节剂的功能进行了研究，但未阐明LmKTT-1a 和Trypsin 的作用方式和位点．文中利用液体NMR 的手段，采用化学位移扰动分析的方法，确定了LmKTT-1a 的loop 区域V10~F17 等氨基酸位点可能参与了与Trypsin的相互作用．进一步采用定点突变的方法验证了NMR 实验的结果，并确认了LmKTT-1a与Trypsin 相互作用最关键的氨基酸位点是K14．该研究结果有助于进一步理解LmKTT-1a具有双功能活性的结构基础．     

Biosensor incorporating cell barrier architectures for detecting <Emphasis Type="Italic">Staphylococcus aureus</Emphasis> alpha toxin

Alpha toxin is a common virulent factor of Staphylococcus aureus and is believed to play crucial roles in pathogenicity induced by S. aureus. Alpha toxin is also known to induce permeability to endothelial cell monolayers in vitro due to the formation of interendothelial gaps. The present study is directed towards measuring alpha toxin using a whole-cell-based biosensor. The biosensor, consisting of a confluent monolayer of human umbilical vein endothelial cells (HUVECs) on a potassium ion-selective electrode, takes advantage of cell permeability dysfunction to detect the presence of small quantities of alpha toxin. When a confluent monolayer of cells was formed on the membrane surface, the response of the electrode toward the marker ion, potassium, was inhibited. Upon exposing this sensor to varying concentrations of alpha toxin for 20 min, an increase in sensor response to potassium was observed. The response thus obtained was indirectly related to the concentration of alpha toxin. The detection limit of this sensor for alpha toxin was found to be 0.1 ng/ml. Cell monolayers were stained with silver nitrate to quantify the formation of intercellular gaps as well as to study the effect of this toxin on HUVECs morphology. A strong positive correlation was observed between the response obtained from the biosensor and the area of the intercellular gaps. Silver staining also revealed the tendency of cells to round up upon being exposed to alpha toxin. Figure Measuring alpha toxin using a whole-cell-based biosensor